Checkout.index not working and some other also

[rashidul]

1.
when i go to this link http://www.visualaidshop.com/en/mcat/index.php and then click on MCAT VisualAd from the left side menu. then http://www.visualaidshop.com/index.php?option=com_virtuemart&page=shop.product_details&flypage=flypage.tpl&product_id=17&Itemid=41 is come.That means my sef url doesn't working properly.Then when i click Ask a question about this product and then click Return to product it behave nicely.Same url now display as http://www.visualaidshop.com/en/shop/13.html

2.
checkout.index not working http://www.visualaidshop.com/index.php?option=com_virtuemart&lang=en&page=checkout.index&Itemid=41&redirected=1&Itemid=41

please provide me a solution.Eagerly interested to urs' reply

My configuration:::joomla 1.0.x
virtuemart:1.1.2
joomsef: 2.2.6